Oestradiol Signalling in the Hippocampus

Since the pioneering experiments demonstrating that oestradiol and related hormones can alter CNS responses other than the control of sexual behaviour, the hippocampus has been utilised as a valuable experimental model for deciphering the multiple roles of sex steroids in the mammalian brain. These roles include the regulation by oestradiol of neuronal and glial proliferation and survival throughout the lifespan, neuroprotection after insults, and the synaptic modulation essential for consolidation of learning and memory. Oestradiol exerts all these functions by various routes, including its receptor-mediated control of transcription, activation of intracellular signal transduction cascades, cross-talk with signalling mechanisms activated by other molecules, such as growth factors, allosteric modulation of membrane proteins, and its antioxidant properties. This review is focussed on the manner in which oestradiol exerts its effects within the hippocampus, and summarizes data on the distribution of known oestrogen receptors as well as how oestradiol modulates nuclear transcription and cell signalling events.